1. Field of the Invention
The present invention relates to a valve arrangement of the kind that includes a valve housing which has an inlet port and two outlet ports for fluid flowing through the housing. The valve housing accommodates a valve element that can move freely between two end positions and that has two surfaces which each co-act with a respective outlet port and which function to close an associated outlet port in respective first and second end positions of the valve elements. The valve arrangement further including means for switching the valve element between the positions.
2. Related Art
Valve arrangements of this kind are know, for instance, from U.S. Pat. No. 4,432,215.
The object of the present invention is to provide a novel and advantageous method of integrating a valve arrangement of the aforesaid kind with a double-acting pump, wherewith there is obtained an arrangement that can be given only a few moveable parts, that will operate quickly and can be positively reset and that lacks any tendency of being set to a neutral position in which both of the outlet ports communicate simultaneously and permanently with the inlet port.
It is proposed to this end in accordance with the invention that the valve arrangement of the aforedescribed kind shall be coordinated with a double-acting pump of the kind that includes two spaces having valve-controlled inlets and outlets for a drive fluid and a pump-transported working fluid respectively, wherein each of said spaces is divided into an operating chamber and a working chamber by means of a respective partition wall in the form of a piston or diaphragm that can move reciprocatingly between end positions, and wherein the partition walls are mutually connected by movement transmission means and perform alternate working strokes under the influence of said drive fluid, during which working strokes working fluid is pressed out from one of said working chambers and drawn into the other of said working chambers, and vice versa, and wherein each of the operating chamber inlets is coupled to a respective outlet port of the valve arrangement and the pump includes resetting means which in the end positions of said partition walls causes the valve element located in one end position to move over only a part of its movement path to the is opposite position.
Further characteristic features of the invention will be apparent from the following objects wherein it is an object of the invention to provide the valve arrangement wherein a resetting means exerts temporarily on the valve element a mechanical or electromagnetic force that exceeds the force exerted by the fluid pressure on the valve element in the opposite direction. Each operating chamber is connected to an associated outlet port of the valve arrangement via a conduit which is adapted to be closed by the associated partition wall when the wall is located in one of its end positions, and in that a fluid bleed passageway extends between the outlet ports and the inlet port common to the outlet ports.
Another object of the invention is that each of the bleed passageways is comprised of a bore or channel that extends through the material of the valve housing or through associated valve element.
A still further object of the invention is that that partition walls include bellow-like structures which are open to the conduits and which function to generate an over pressure in an associated conduit when closing the conduit operating chambers are located close together on both sides of the valve arrangement, and in that the partition walls are provided with pins which each extend into a respective outlet port and, when the partition walls are in their inner end positions, act on an associated valve element surface to initiate resetting the valve element.
It is an object of the invention that the valve element is mounted on one end of a freely pivotal arm and has the form of a valve plate or disk which includes mutually opposite surfaces for alternate co-action with a respective outlet port.
A further object of the invention is that the valve element is connected mechanically to and adapted to drive a further valve element between two positions in which it connects either one or the other of two fluid inlet ports to a fluid outlet port which is common to the two inlet ports.
A still further object of the invention is that the pivotal arm carries on a second end a further valve plate or disc that has mutually opposite valve-element surfaces for co-action with a respective valve port in a further valve space.
Another object of the invention is that the operating chamber outlets are connected to the fluid inlets of the further valve element.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.